Question 1

What actually causes food poisoning, and which pathogens matter?

Accepted Answer

A small number of organisms account for most cases, and they behave differently enough that **the same precaution does not work for all of them** — which is why general advice to "cook things properly" is incomplete.

**The ones that matter most:**

**Campylobacter** — the most common cause of bacterial food poisoning in the UK, overwhelmingly from raw poultry. It does not need to multiply to make you ill; a very small dose is enough. **This is why washing chicken is actively harmful** — it aerosolises bacteria across the kitchen without reducing the number on the meat, which cooking would have killed anyway.

**Salmonella**, from poultry, eggs and cross-contamination. Vaccination of laying flocks has substantially reduced egg-related risk in some countries.

**Norovirus**, which is a virus rather than a bacterium, spreads person to person and via shellfish and contaminated surfaces, and is **not affected by anything that kills bacteria**. Alcohol gel works poorly against it; soap and water work.

**Listeria**, which is rarer and much more serious, particularly in pregnancy and for immunocompromised people. Its distinguishing feature is that it **grows at refrigerator temperatures**, which is why chilled ready-to-eat foods carry specific advice.

**E. coli O157**, from undercooked beef and cross-contamination, dangerous because of the small dose required and the severity in children.

**Clostridium perfringens and Bacillus cereus**, associated with food cooled and held badly rather than cooked badly.

**Why symptom timing is informative.** Very rapid onset — within hours — usually indicates a **pre-formed toxin**, which cooking does not destroy. Onset over a day or more indicates the organism multiplying in you.

**What actually prevents most of it:**

**Separation of raw and ready-to-eat**, including boards, hands and surfaces.

**Cooking to temperature**, not to appearance.

**Cooling quickly** and refrigerating within two hours.

**Handwashing with soap.**

**Respecting use-by dates** on high-risk chilled foods.

General information, not medical advice.

Question 2

Why must chicken be cooked through when steak can be rare?

Accepted Answer

Because of where the bacteria are. In a whole cut of beef, contamination is on the surface. In poultry, it can be throughout the meat. Bacteria arrive on meat during slaughter and processing, and

Question 3

Is the five-second rule real, and how does cross-contamination actually work?

Accepted Answer

No — transfer of bacteria to dropped food is effectively instantaneous — though the amount transferred does increase with contact time, which is the grain of truth the rule was built on. What matters

Question 4

Does cooking destroy the nutrients in food?

Accepted Answer

Some, sometimes — and it increases the availability of others, which is the part usually left out. Whether cooking is a net loss or gain depends entirely on the nutrient and the method. What cooking

Question 5

Where should food actually go in a fridge?

Accepted Answer

Placement matters for two separate reasons — temperature varies within a fridge, and cross-contamination runs downwards — and getting the second wrong is the one that causes illness. The temperature

Question 6

What is the difference between pasteurised, UHT and raw milk?

Accepted Answer

The difference is how much heat the milk has been through, and that determines both safety and how long it keeps. Raw milk is unheated, straight from the animal after filtering and chilling. It

Question 7

What is the difference between "best before" and "use by"?

Accepted Answer

Use by is about safety. Best before is about quality. Confusing them causes both unnecessary waste and genuine risk, in opposite directions. Use by appears on foods that become unsafe as they age,

Related Questions